It was the biggest single question surrounding Mark Millar's appointment as Fox's "Marvel Tsar", I suppose, and he's answered during a Q&A with SFX magazine and their readers.
One Joe Steiner asked:
Will the upcoming reboot of the Fantastic Four share a universe with the future X-Men films?
To which Millar replied:
Without question I think you have to see some of these guys showing up in each other's movies. I think the most exciting thing in superhero movies, until The Avengers came along, was when Nick Fury showed up in Iron Man. Even though it was a guy with an eye patch it was really cool – and I expect we will see more of that.
This has some implications, I suppose for the X-Men universe, but there are a multitude of ways in which it might be handled. I'm more immediately interested in how much the Fantastic Four film will acknowledge the existence of mutants, or try to place itself in the X-world.
It's remarkable how Marvel's decision to press ahead and create a "Cinematic Universe" has had an effect on how superhero cinema is being approached these days. And it's almost as remarkable that nobody has tried it with other genres yet.
I guess The Bourne Legacy and the latest Fast and the Furious film are based on similar models, but there's far more potential to yet be tapped, I'm sure – both creatively and commercially. It looks like The Mortal Instruments will be the first to take a crack, with a prequel in the works, a gaslamp fantasy to sit alongside the present-day stories of City of Bones and its follow-ups.
Perhaps there's been an assumption is that comic book fans were ready for this, having become used to it on the the printed page. That would suppose, though, that this idea is a hard one for an audience to grasp and I really don't think it is.